An IC is a device that includes numerous electronic components (e.g., transistors, resistors, diodes, etc.) that are embedded typically on the same substrate, such as a single piece of semiconductor wafer. These components are connected with one or more layers of wiring to form multiple circuits, such as Boolean gates, memory cells, arithmetic units, controllers, decoders, etc. An IC is often packaged as a single IC chip in one IC package, although some IC chip packages can include multiple pieces of substrate or wafer.
Electronic Design Automation (EDA) tools are automated tools used in IC design. Placement and routing are steps in automatic design of ICs in which a layout of a larger block of the circuit or the whole circuit is created from layouts of smaller sub-blocks. During placement, the positions of the sub-blocks in the design area are determined. These sub-blocks are interconnected during routing. A placer assigns exact locations for circuit components within the IC chip's core area. A placer typically has several objectives such as minimizing total wire length, timing optimization, reducing congestion, and minimizing power. The placer takes a given synthesized circuit netlist with a technology library and produces a placement layout. The layout is optimized according to a set of placer objectives.
The maximum delay through the critical path of a chip determines the clock cycle and, therefore, the speed of the chip. The timing optimization is performed to ensure that no path exists with delay exceeding a maximum specified delay.